


Clockwork Trio - a Will/Tessa, Will/Jem, Tessa/Jem erotic TID fanfic

by NonniePlume



Category: Cassie Clare - Fandom, Infernal Devices Series - Cassandra Clare, Shadowhunter Chronicles - Cassandra Clare, TID - Fandom
Genre: Explicit Sexual Content, F/M, Lemon, M/M, Multi, Polyamory, Shadowhunters - Freeform, Smut, Threesome - F/M/M
Language: English
Status: Completed
Published: 2015-02-22
Updated: 2015-02-22
Packaged: 2018-03-14 13:40:54
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,270
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3412724
Author URL: https://archiveofourown.org/users/NonniePlume/pseuds/NonniePlume
Summary: <blockquote class="userstuff">
              <p>Tessa shape-changes into her husband's former parabatai. Brother Zachariah visits, complaining of strange dreams....  (Basically, my attempt at imagining a three-way scenario within the universe set out in the books.)<br/></p>
            </blockquote>





	Clockwork Trio - a Will/Tessa, Will/Jem, Tessa/Jem erotic TID fanfic

**Author's Note:**

> WARNING: explicit adult content (M/M and M/F); not for the eyes of proper Victorian ladies or gentlemen. Also, this takes place after Clockwork Princess, so BEWARE SPOILERS. 
> 
> Feedback welcome.

Tessa found Will staring out their bedroom window, a pensive set to his shoulders. She came to his side and glanced from the troubled look on his face, to the scene outside the window. It was midnight in London. The night sky was black and unusually clear, the stars were bright points of light, clearly visible above the city.

"Will,” she said, nuzzling gently at his shoulder, “what is it?” 

Will turned and bumped his head affectionately against hers. The smallest hint of a frown lingered at the corners of his mouth. “Nights like this remind me of him,” he said. “We spent clear nights hunting in the streets.”

“Oh,” Tessa’s voice caught. She did not need to ask who Will meant by ‘him.’ Nights like this brought Jem sharply back into her own memory. Sometimes she even imagined she could hear his violin playing in a distant room. 

Will turned to her with a pained expression in his eyes. "Don't you ever wish we could see his face, the way it looked before the vows that left those scars on his cheeks? The way he looked when we loved him best.”

“Will,” Tessa hesitated. Several months back, she had walked past the Royal Albert Hall and heard the most beautiful strains of music floating through Hyde Park. The lovely sounds had seemed to stab her painfully in her heart, making her miss Jem so much that when she'd arrived home, shaken and heartsick, she'd locked herself alone in a bedroom and done something she had vowed never to do again--she had used her ability to take on the form of one who had not given his express permission for her to do so--she had made herself look like Jem. She had felt horribly guilty as she took hold of the spark of life that was uniquely Jem's, but a sort of relief had settled over her as his shape formed over her body. She had studied his beautiful, delicate face in her mirror. It was a moment to feel close to him again. 

She'd apologized in her mind to him for invading his soul and had been surprised to find that she could not feel any connection to his thoughts or emotions, the way she always had before, when taking on another's form. Instead, it was as if a thick pane of glass separated him from her. At the end of the experience, she had convinced herself that perhaps she had not invaded Jem's privacy at all. She could hardly imagine that he could have noticed her intrusion when she had not been able to feel him at all. 

“There is a way that you can look at Jem's face," Tessa said now. "What I mean to say is,” she looked down shyly, “I can look like him.”

“Tess,” Will breathed softly. "Of course. Would you?”

Tessa nodded, secretly pleased. “Help me out of these clothes,” she said. “Jem’s bigger than I am, and I don’t want to break a rib when I come into his form in this corset.”

Will emitted a snort of laughter at that thought, and quickly helped Tessa strip her jacket, overskirt, bustle, and two petticoats. He slowly loosened her stays and let her corset slide to the floor between them. Tessa stood in nothing but a white silk chemise, bloomers, and stockings. 

Will seemed to hesitate for a moment. “You can’t make me see James in ladies’ underclothes,” he said. “I won’t be able to do anything but laugh.” 

Tessa smiled and pulled the chemise over her head. At Will's frown, she stepped out of her bloomers and rolled down her stockings too. She stood before her husband, completely naked. 

Will paused thoughtfully. “Will Jem be naked too, then?” he asked.

“Yes,” Tessa said. “Would that make you uncomfortable?”

“Me, uncomfortable?” asked Will. “No, of course not. It wouldn’t be the first time I’ve seen Jem naked.”

Tessa raised her eyebrows.

Will grinned in response. “Training can sometimes call for iratzes below a parabatai's' trousers. But I was thinking of you -- and of him.”

“Of him?” Tessa asked. 

“Yes, of Jem. Would it not be a violation of his privacy?”

“Oh, I hardly think you need worry about that,” Tessa said. “You forget that we were once engaged to be married. There isn’t much of Jem I haven’t already seen--” Tessa blushed suddenly, realizing that she had revealed more than she had intended. “I mean, that is -- it was nothing so far as you and I--.” 

Will touched her lightly on the shoulder. “I’m glad to hear that you had time for intimacy together, before he was--separated from us,” he said. He stepped back from her. “Go on,” he said eagerly, “change.”

Tessa reached inside herself and thought of Jem, his steady spirit, the calm set of his shoulders, the softness of his hair, the quicksilver light of his eyes--and the change came over her quickly. She felt herself lengthen and opened her eyes. 

Her view of Will was slightly obscured by a few fine strands of bright silver hair. She shook it out of her eyes and took a step closer to Will.

“Jem,” Will said, “can you--can he--feel this? Does he know what’s happening?”

Tessa searched inside herself for the spark of life that fueled the change, but it was as before--an intangible barrier separated her from the piece of Jem that she had latched onto. “I don’t think so,” she said in Jem’s voice. “The Silent Brothers--they are not truly alive.”

Will nodded. “I can hear you, in his voice,” he said. He came up to her, placed his hands carefully on her shoulders, and stared into her face like a starved person gazing upon a feast. “You do look just like him," he said hoarsely, "except, of course, that you haven't any marks.” He gently brushed his hand over her bare shoulder, the place where Jem's parabatai rune should have been. 

“Jem,” Will whispered. He was so close to her face, and grasping her shoulders with such intimate affection, that for a moment, Tessa thought he might kiss her. To Tessa’s extreme embarrassment, Jem’s body reacted to Tessa’s thought. Tessa felt a foreign tightening sensation in her groin and blushed all the way to her toes.

Will noticed, too. Tessa could hardly hide it from him, when the evidence of her interest was literally growing in front of him, as she stood naked, in Jem’s form. 

“Tess,” Will said. “It is Tess, isn’t it? This isn’t the Jem part of you?”

“Of course it’s me,” Tessa said, looking down at Jem’s body in chagrin. “I thought for a moment that you were going to kiss me, which is absurd, of course, since I’m in Jem’s body.”

“It’s not completely absurd,” Will said. “I know you’re Tessa, even if you are in Jem’s body.”

Tessa blushed and tried to hide her face, but Jem’s hair was too short to hide behind. “I don’t know how to--relax the muscle,” Tessa said. “I--perhaps I’d better go back into my own body.”

Will caught at her wrist. “Don’t change yet.” He took her hand gently. “Let me help you,” he breathed in her ear, sending a thrill down her spine. His lips pressed hard and hot against hers, his teeth clacking against hers as their mouths opened together. It was different from any kiss they’d shared before -- full of a passion unlike that in their marriage. Tessa had to wonder if some part of her husband had been dreaming of kissing his parabatai for years. She didn’t spend much time on the thought. Will’s tongue was gently caressing the inside of her--Jem’s--mouth, forcing all coherent thought out of her mind.

Will broke off abruptly. She brought her fingertips to her lips. They felt hot and stung slightly from the force of the kisses. She stared after Will in wonder as he led her--still in Jem’s form--to their bed, and pulled her gently down. “Will,” Tessa whimpered miserably, as he wrapped his arms around Jem’s chest. The unfamiliar organ below her waist had only swelled further with Will’s kisses and now stood fully erect, quivering with the strength of her desire. “Will, I don’t know how to deal with this” she said. 

“Allow me,” Will said, and stroked Jem’s manhood with his long-fingered hand, gently, at first, and then harder.

“Will,” Tessa said huskily, in Jem’s voice. “Will, this--this is perverse. Is it not against Shadowhunter law?”

“For a man to engage in marital relations with his wife?” Will asked playfully. “I hardly think so.” He gently pushed against Jem's chest until Tessa lay prone on the bed. Then he brought his lips, warm and soft, to the very tip of Jem, all the while continuing to grasp Jem’s shaft with his hands. Tessa was making soft cooing noises in the back of Jem’s throat, a sound she was fairly certain Jem would never make, but which came out in Jem’s voice all the same. “By the angel,” she whispered in Jem’s voice. “I certainly won’t stop you if you’re determined to see this through.” She groaned as Will’s tongue dragged over Jem’s head, and, though she could hardly comprehend what she was doing, she thrust forward with her hips, sending Jem's length deep into the back of Will’s throat. Will chuckled around Jem, sending vibrations through her body. Jem's organ twitched and Will only sucked harder. A flood of sensation crashed through Tessa. “Will,” she moaned, feeling herself lose hold of the change in her moment of ecstasy. “Oh, Will!”

In the very last instant before Jem’s form slipped away, Tessa felt a fleeting presence, one that made her think of a breath of fresh air after a long summer day closed up in the stuffiness of the Institute--Jem, her Jem, as she had known him before, when they had once been engaged to be married. Then she was just herself, trembling with pleasure in her own body.

Will laughed softly as she gasped and opened her own eyes. “My Tessa,” he said, kissing her tenderly on the lips. For a moment, Tessa tasted Jem on Will’s tongue, and the sweet, burnt sugar taste of the demon drug that always came with Jem. That recognition sent a double-thrill down her spine. It was like she was in bed with both of them. But when Will brought his lips to hers again, it was all Will. Will, covering her in sweet fluttering kisses as she relaxed her head back onto the pillow. Will, tenderly brushing her now sweaty hair back from her face. Will, bringing a low moan of protest to the back of her throat as he broke away from their kiss.

“Will?” she asked breathlessly. Will was furiously stripping the clothes she had forgotten he was still wearing. “My turn now, Tess.” He lowered himself over her.

“Shall I go back to being Jem?” she asked.

“Certainly not,” he said, nibbling at her neck. “I didn’t mind you in Jem’s body. I think a part of me has always felt that he belonged with us. You would have married him, after all, if things hadn’t happened the way they did. I wanted him to have a part in our marriage, especially since it so obviously pleased you as well. But I much prefer you in this form.”

As if to prove his point, he trailed his fingers over her body, lingering in particular over her bosom. Tessa sighed happily and peered at Will through half-lidded eyes. 

“Don’t fall asleep yet, Tess,” Will said. He sucked on one of her nipples, hard.

“Ow,” Tessa complained, although the action had served Will’s purpose of arousing her once more. She ran her own hands over the strong muscles of Will’s back and shoulders, ghosting her fingers along the base of his neck and down his chest, feeling his skin prickle beneath her trailing hands.

"Tess," Will said, "Are you ready?"

"Yes." She positioned the tip of him at her entrance. 

"Oh, my sweet Tess," he said, rubbing the tip of himself up and down over the sensitive nub of flesh at the top of her folds. 

He rocked against her, sliding between her thighs. Tessa moaned and pressed her face into his shoulder, gripping his back and pulling him to her, closer, closer, closer.

He pulled back from her slightly so he could kiss her fiercely on the mouth as he thrust inside her with a hungry growl. Tessa closed her eyes, a flood of sensations building inside her. Will rocked against her eagerly, as Tessa's pulse raced and stuttered. Will groaned and shuddered inside of her, breathing heavily against her chest as Tessa closed her eyes into oblivion. 

“I love you, Will,” Tessa whispered into his neck. 

“I love you, Tess,” he said, kissing her softly on the lips.

Exhausted, she melted into the bed, wrapping her arms around Will's, both of them falling into a soft doze. 

 

It was some time later when Tessa felt Will start awake beside her. She raised her head groggily and blinked up at him. 

“Someone’s here,” he said. “A Shadowhunter. I heard the door.”

“In the middle of the night?” Tessa whispered. “Has something happened?”

“Sleep, darling,” he said. “I’ll go down to see who it is.” He slipped quietly out their bedroom door.

Tessa sighed and lay back on the bed, but now that she was awake, it was hard to find sleep again. She blinked and rubbed her eyes, wondering who would come to the Institute at this hour.

The door inched gently open, and Will stepped quietly in. “Tess,” he whispered into the darkness, “are you awake?”

“Is something wrong?” Tessa asked. 

“No,” said Will, “nothing’s wrong, but if you’re awake, you might like to get dressed. It’s Jem, come to visit us.”

“Jem!” Tessa exclaimed, standing up and throwing on a dressing gown. “At this hour?”

Will lit a lamp and pulled the bedroom door open the rest of the way. Brother Zachariah glided in.

I had a most peculiar dream, Brother Zachariah’s voice said in her mind, in the way of the Silent Brothers. Involving the two of you… and… me. 

Will and Tessa exchanged a guilty glance. “About that,” Will said. “We were only having a bit of fun. You know, Tessa needs to experiment with her abilities, every now and then.”

It stirred thoughts in me... desires that I had not thought still possible…. I have not had thoughts of that nature for quite some time, Brother Zachariah said.

“No,” Tessa whispered, her cheeks aflame with embarrassment. “I imagine not.”

“We’re sorry to have made you uncomfortable, Jem,” Will said. “It was my fault. I told Tessa that I missed you, and she was only trying to oblige me. I shan’t ask for it again.”

Brother Zachariah gave Will an imperturbable look. It was a very strange experience for me, he said.

“For me too, obviously,” Will said. “It was all for Tessa.”

Yes, of course, said Brother Zachariah. You know I would do anything for Tessa, just as you would.

“Of course I know it,” Will said quietly, and Tessa knew from the way he said it that he felt guilty all over again about the way things had turned out between the three of them.

“James,” Tessa said gently. “I’m so glad that you’ve come, but was there a particular reason why you chose to visit in the middle of the night? Were the thoughts so disturbing that you could not wait till morning?”

Not disturbing, Brother Zachariah said, they were… arousing.

“Arousing?” whispered Tessa.

But not... fulfilling. Brother Zachariah said.

“Oh, Tess,” Will yelped, “we’ve been perfect beasts. We’ve pleasured ourselves, at the expense of arousing Jem, and there he was, stuck in his own body, alone.”

Tessa looked from Will to Jem and back at Will again, bewildered.

"You will recall," Will said to Tessa, "that you changed back into yourself, at the end? He... hasn't found gratification." He turned to Jem, "what shall we do, James? You're the holy brother, what do you suppose is allowed in these circumstances? I, for one, am willing to put convention aside, if you will only tell us how we can help you." He looked meaningfully at Tessa.

Tessa stared from him to Jem. "Will, you aren’t suggesting that Brother Zachariah and I..."

"Temporarily take up residence in our marriage bed together?" finished Will. "Only if you're both willing, of course."

"But... Brother Zachariah is..." She stopped herself short of saying 'not exactly alive,' because he was standing there with them and was obviously alive.

Tessa is correct, Brother Zachariah said. In my own form, I am incapable of feeling desire. But through you, he said to Tessa, I feel... much.

Tessa looked at him sympathetically. "Then I certainly hope you know that I would gladly do anything I can to make you comfortable," she said. 

Brother Zachariah seemed to hesitate, though his outward demeanor remained impassive. You will have to feel for me Tessa, he said. I am not certain I can inhabit desires of my own, as I am. 

"Go on," Will said with a nod to Tessa, "change form again."

Tessa closed her eyes and took hold of Jem's form again. She felt the silky fabric of her dressing gown grow snug around Jem's wider shoulders as she opened her eyes in Jem's body. She gingerly shrugged out of the dressing gown and looked expectantly at Brother Zachariah and Will. 

Will and Brother Zachariah exchanged a long glance. Without a word, Will turned to Tessa, brought his hands to either side of her face, which looked like Jem's face. He kissed her deeply. 

Tessa heard Brother Zachariah inhale softly beside them. Just as before, the kiss sparked a fire low in her belly. Will's fingers swept past Tessa's temples into Jem's fine hair, tugging slightly, and firmly stroked down her shoulders, around her neck, over her back, and further down. Tessa felt her buttocks clench involuntarily in reaction to Will's long fingers crackling like fire over the hardened muscles, raising a sizzling heat all along Jem's pale skin. 

Tessa barely paid heed as Will stripped himself of the gear he had somehow managed to dress in before letting Brother Zachariah up. They inched slowly closer to the bed, dropping black leather gear to the floor as they went. 

"Tess," Will murmured, between hard, sucking kisses, "you're going to have to hold onto the change this time." Tessa blinked open her eyes as Will broke off kissing and bent facedown over the bed. 

She stared blankly at his bared dragon tattoo and looked back at Brother Zachariah. "I don't know what to do," she said hoarsely, in Jem's voice. 

Brother Zachariah came to stand beside her. He rubbed his thumb along the tip of Jem's member, which had begun to ooze, and ran the same thumb around Will's opening. 

Tessa swallowed. "Are you both sure about this?" she asked, as Brother Zachariah gently slid a finger between Will's cheeks. 

"It going to feel marvelous," said Will, "for all three of us."

Nervously, Tessa positioned herself behind Will. She looked to Brother Zachariah, but he had eagerly moved forward and was using his own hands to gently guide the unfamiliar body part that Tessa now controlled into Will. 

All three of them exhaled shakily as Tessa dipped slowly into Will. 

"Alright, Tess," Will said tightly. "Don't lose the change."

Tessa tried to concentrate on being Jem, on the lightness of his spirit, his buoyant nature, his steady strength and reliable loyalty. But there was nothing steady or reliable about what the three of them were doing now, and as she pushed closer and closer to the edge, Tessa felt her hold on the change slipping. 

"By the Angel!" Will rasped, jerking taut beneath her. It was enough to break her already fragmented concentration. With a gasp, she opened her eyes in her own body. 

Will seemed to be trying to maintain his composure, in light of Tessa and Jem's obvious frustration, but he had clearly enjoyed himself. He lay curled on his side in a lower corner of the bed. Tessa averted her eyes from the slippery mess on the edge of the bedspread, and looked back at Brother Zachariah. 

A peak had formed midway down the front of Brother Zachariah's robe--one that had not been there before. "Jem," she said, with wonder. "We did it. Your body--"

Brother Zachariah looked down at the tent his erection had formed of his robe. That is curious, he said. I had not thought it possible. I wonder--. He looked questioningly at Tessa. 

Tessa took a step closer to him and slowly slid her hand into his robe. With trembling fingers, she untied the rope sash at his waist and slid the parchment white cloth off Brother Zachariah's shoulders. 

He still had Jem's beautiful body, no longer painfully thin, but corded with strong muscles all along the lean frame. His skin was still ghostly pale, and patterned all over with inky black runes. 

She brought her lips to his. They were cool, but velvety soft. They warmed to her caress. 

Tessa closed her eyes and willed herself to forget for a moment that this was Brother Zachariah, whose slow, deliberate movements were mechanical and inhuman. She imagined instead that this was her Jem, the Jem she had not been able to keep her hands off through a carriage ride. The Jem she had been desperate to marry as soon as possible. 

Kissing him fiercely, Tessa spun Brother Zachariah's thin but muscular body closer to her own, pulling him over her as she fell backwards onto the bed, dragging him on top. She hooked her legs around his hips.

"Jem," she breathed against his cool lips. A tear slid out of the corner of her eye. It was almost too much, having him in bed with her-- so close to what she had once desperately hoped for, yet so markedly different from what she had imagined. 

No tears, qin ai de, Brother Zachariah's voice was gentle as a whisper in her mind, as one of his cool hands brushed a tear from her cheek. She knew, without knowing how she could tell, that he spoke only to her. 

She sniffed and rolled onto her stomach so he could not see the tears on her face and she could not see his scarred cheeks. "Jem," she whispered into the bed, "I'm just so happy that you're here." She bent her knees under her, raising her hips invitingly. 

Brother Zachariah brought cool hands to either side of her hips and entered her soundlessly, smoothly. His shaft was also cool to the touch. It felt nothing like what Tessa might have imagined it would feel like to be with Jem, but it was not unpleasant. Tessa closed her eyes, her tears drying away, surrendering to the slow, gliding rhythm--but even without seeing his face, it was hard to ignore that this was not her Jem, but Brother Zachariah. 

Tessa heard Will rouse himself from his half-dozing stupor at the foot of the bed and caught a half glimpse of him hovering anxiously over them. She parted her lips to speak--whether to ask Brother Zachariah to stop, or to ask Will to leave them be, she hadn’t fully decided--any thought she’d had was chased away when Will applied one of his hands gently to her front, igniting Tessa's clitoris. She arched her hips upward, bringing Brother Zachariah even deeper inside her with a wordless cry. 

Will put his other hand to use, moistening his forefinger along Tessa's wet inner thigh, and sliding it beyond Tessa’s eyesight, somewhere behind Brother Zachariah. Brother Zachariah emitted a strangled noise and a deep thrust out of rhythm had Tessa criying out breathily. Brother Zachariah came to a pulsing, stuttering climax inside her, sending her into rippling shockwaves of pleasure. 

Tessa dissolved into a jumble of limbs--she, Will and Jem, all tangled together, entwined on the pillows, gasping for air. Her breathing had almost slowed to normal when Brother Zachariah rose from the bed and dressed in his robes. 

Thank you, my friends, he said, after several long breaths. I am grateful to you both, though, I think, perhaps, it would be best if we never spoke of this episode. 

"And here I was, thinking we could make it a regular occurrence," Will said lazily from the bed. 

Tessa raised her head languidly to look at him. 

"At least once annually?" asked Will. 

It was not an unpleasant experience, but for the sake of decorum, ought not be repeated, at least, not so long as I am a Silent Brother, said Brother Zachariah. In future, please don't unintentionally invite me into your bedroom. 

"Fair enough, Brother Zachariah," Tessa said with a small smile. "Next time, we'll intentionally extend an invitation."

Will pulled Tessa close to him and kissed her temple. "I'll let you see yourself out, Jem," he murmured over a yawn. "Tessa and I need a bit more time to recover." He snuggled against Tessa, burying his face in her hair. 

"Mmm," Tessa said sleepily. "Goodbye, 'til next time."

Sleep well, both of you. It was hard to tell for sure, but Tessa thought she detected affection and a note of humor in the Silent Brother's detached voice. She smiled to herself and drifted blissfully to sleep. 

The End.


End file.
